Effects of parasitism on cellular immune response in sheep experimentally infected with Haemonchus contortus - Ortolani, Enrico Lippi; Leal, Marta Lizandra do Rêgo; Minervino, Antonio Humberto Hamad; Aires, Adelina Rodrigues; Coop, Robert L; Jackson, Frank; Suttle, Neville F (Veterinary Parasitology, 2013)